JP2016115960A - Video recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video recording device that can surely record a quick-motion event occurring incidentally.SOLUTION: A video recording device has video input means 10 for inputting pictures into a frame memory 40, moving picture constructing means 60 for constructing a moving picture from a memory 40, frame accumulation means 30 for dividing the input picture into frames and writing the frames into the memory 40, and frame reference means 50 for reading out a frame satisfying a condition of the moving picture constructing means 60 from the memory 40. The frame accumulation means 30 has writing position determining means 31 for determining a writing position at which a frame is written into the memory 40. The frame reference means 50 has reading position determining means 51 for determining a reading position at which a frame is read out from the memory 40. Frame rate restricting means 20 for thinning out frames constituting the input picture to reduce the frame rate to a restricted frame rate, and restricted frame rate determining means 80 for calculating a restricted frame rate based on the writing position and the reading position are provided.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a video recording apparatus, and more particularly to a video recording apparatus capable of reliably recording an event that occurs accidentally and has a fast movement.

  Conventionally, there are two types of video recording apparatuses, a continuous recording type and an instantaneous recording type. The continuous recording type is a type in which video is continuously recorded for a long time, such as a security camera or a surveillance camera (see, for example, Patent Document 1). The instantaneous recording type is a type that records a high-quality video only when something happens, such as a high-speed camera or a drive recorder (see, for example, Patent Document 2).

  As a problem common to these video recording apparatuses, there is a problem caused by a huge size of moving image data. Video data that records video, that is, images that change over time, generally has a huge size. It is not uncommon for the size of these moving image data to exceed 1 gigabyte, and in moving image data that records high-quality, long-time images, the size may reach 1 terabyte. Needless to say, storing and moving such huge video data is extremely difficult.

  In order to avoid this inconvenience, the video recording apparatus generally needs to consider that the size of the moving image data does not become too large at the expense of either recording time or video quality. Of the video recording apparatuses, the continuous recording type secures the recording time by reducing the video quality, and the instantaneous recording type secures the video quality by limiting the recording time.

JP-A-8-255293 JP 2014-220803 A

  Regarding video recording, there is a need to reliably record events that occur infrequently and accidentally, for example, abnormal machine operations that occur only once in a few days. However, in the video recording apparatus as described above, it is necessary to select one of recording time and video quality, and it has been difficult to meet such needs. In the continuous recording type in which the recording time is prioritized, although the time is not overlooked, the fast movement of the object cannot be clearly recorded. Moreover, in the instantaneous recording type in which video quality is prioritized, an event cannot be recorded completely if the timing is not met. That is, no matter what type, the above needs could not be met accurately.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a video recording apparatus that can reliably record an event that occurs accidentally and moves quickly.

  In order to achieve the above object, the invention described in claim 1 is a video recording apparatus comprising at least one video input means, a frame memory, and a plurality of moving image forming means, wherein the plurality of moving image forming means. However, the present invention is characterized in that the video recording apparatus operates simultaneously while creating moving images having different frame rates.

  In addition to the configuration of claim 1, the invention described in claim 2 further includes a frame storage unit that decomposes the video input by the video input unit into frames and writes the frame into the frame memory. Frame reference means for reading out the corresponding frame from the frame memory in accordance with the condition from the frame storage means, the frame storage means is provided with a write position determination means for determining a position to write the frame to the frame memory, the frame reference The means includes reading position determining means for determining a position for reading the frame from the frame memory.

  According to a third aspect of the present invention, in addition to the configuration of the second aspect, the frame rate limiting means for thinning out the frames constituting the video input by the video input means to reduce the frame rate to a predetermined limited frame rate. And a limited frame rate determining means for calculating the limited frame rate based on a write position determined by the write position determining means and a read position determined by the read position determining means.

  According to a fourth aspect of the present invention, in addition to the configuration of the third aspect, the limited frame rate determining means calculates a limited frame rate that is lower than the frame rate of the video input means and exceeds zero. It is characterized by.

  In addition to the configuration described in claim 3 or 4, the invention described in claim 5 displays the limited frame rate or a value correlated with the limited frame rate.

  In addition to the configuration described in any one of claims 3 to 5, the invention described in claim 6 further includes means for arbitrarily starting and / or ending the operation of the frame rate limiting means. And

  According to the first aspect of the present invention, there is provided a video recording apparatus including one or a plurality of video input means, a frame memory provided in accordance with the number of video input means, and a plurality of moving image forming means. Since a plurality of moving image constituting units operate simultaneously while creating moving images having different frame rates, it is possible to set a plurality of video recording plans having different balance between recording time and video quality. If a plurality of video recording plans are combined in accordance with the recording target, video recording that is not overlooked in terms of both recording time and video quality can be realized.

  According to the second aspect of the present invention, since the writing position determining means for determining the position for writing the frame into the frame memory and the reading position determining means for determining the position for reading the frame from the frame memory are provided, The writing position and the reading position can be specified, and thereby the current use status of the frame memory can be known. By grasping the usage status of the frame memory in this way, it is possible to provide a video recording apparatus that can prevent video loss due to the frame memory being full and can reliably record video.

  According to the third aspect of the invention, the frame rate limiting means for thinning out the frames constituting the video input by the video input means to reduce the frame rate to a predetermined limit frame rate, and the writing position determining means determine A limited frame rate determination unit that calculates the limited frame rate based on the write position and the read position determined by the read position determination unit is provided, so that the frame memory can be prevented from being full and video can be recorded reliably. Video recording apparatus can be provided.

  According to the fourth aspect of the present invention, since the limited frame rate determination means calculates a limited frame rate that is lower than the frame rate of the video input means and exceeds 0, even if the frame memory is almost full Therefore, it is possible to provide a video recording apparatus capable of continuously recording video without stopping video recording at a low frame rate.

  According to the fifth aspect of the present invention, since the limited frame rate or a value correlated with the limited frame rate is displayed, side effects such as video quality degradation caused by thinning out of the frame rate occur. The possibility is shown to the operator in an easy-to-understand manner, and if necessary, the video recording plan can be reviewed.

  According to the sixth aspect of the present invention, since the means for arbitrarily starting and / or ending the operation of the frame rate limiting means is provided, side effects such as degradation of video quality due to frame rate decimation may occur. If this is not allowed, the operation of this function can be stopped.

It is a figure for demonstrating the basic concept regarding a moving image. 1 is a block diagram showing an outline of a video recording apparatus 1 according to an embodiment of the present invention. It is a figure which shows the structure of the frame memory 40 concerning the embodiment. It is a figure which shows the method to produce preservation | save animation A7 from the low frame rate image | video A2 which concerns on the embodiment. It is a figure which shows the method to produce preservation | save animation A7 from the low frame rate image | video A2 which concerns on the embodiment. It is a figure which shows the method to produce preservation | save animation A7 from the low frame rate image | video A2 which concerns on the embodiment. It is a figure which shows the method to produce preservation | save animation A7 from the low frame rate image | video A2 which concerns on the embodiment. It is a figure which shows the method to produce preservation | save animation A7 from the low frame rate image | video A2 which concerns on the embodiment. It is a figure which shows the method to produce preservation | save animation A7 from the low frame rate image | video A2 which concerns on the embodiment. It is a figure which shows the relationship between write-in position A8 and read-out position A9 in the frame memory 40 concerning the embodiment. It is a figure which shows the relationship between write-in position A8 and read-out position A9 in the frame memory 40 concerning the embodiment. It is a figure which shows the example of the relationship between the frame memory usage rate and restriction | limiting frame rate A10 which concern on the embodiment. It is a figure which shows the example of the time transition of the frame memory usage rate which concerns on the embodiment. It is a figure which shows the example of temporal transition of restriction | limiting frame rate A10 which concerns on the embodiment. It is a figure which shows the example of the relationship between the frame memory usage rate and restriction | limiting frame rate A10 which concern on the embodiment. It is a figure which shows the example of the time transition of the frame memory usage rate which concerns on the embodiment. It is a figure which shows the example of temporal transition of restriction | limiting frame rate A10 which concerns on the embodiment. It is a figure which shows the example of the relationship between the frame memory usage rate and restriction | limiting frame rate A10 which concern on the embodiment. It is a figure which shows the example of the time transition of the frame memory usage rate which concerns on the embodiment. It is a figure which shows the example of temporal transition of restriction | limiting frame rate A10 which concerns on the embodiment. It is a figure which shows the example of a screen of the video recording apparatus 1 which concerns on the embodiment.

  Embodiments of the present invention will be described below.

  1 to 21 show an embodiment of the present invention.

  First, the basic concept regarding moving images will be described with reference to FIG.

  Before describing the video recording apparatus 1 according to the embodiment of the present invention, a basic concept regarding moving images will be described. In general, a moving image is an image to be converted with time, and its substance is an array of still images called “frames”. The entity of each frame is a two-dimensional array of “pixels” representing the colors of individual grid points arranged at equal intervals in the vertical and horizontal directions. The number of pixels that make up a frame is called "resolution". Each frame has a “frame length” that is a time to be displayed on the screen. The relationship between these concepts is shown in FIG.

  For many videos, the resolution and length are constant throughout all frames. A value of 640 × 480 pixels (VGA) is used as the resolution, and 1/30 second is used as the frame length. The reciprocal of the length of the frame, that is, the number of frames per unit time is called a “frame rate”.

  Based on the above basic concept regarding moving images, the video recording apparatus 1 according to the embodiment of the present invention will be described below.

  A video recording apparatus 1 according to the present embodiment is shown in FIG. The video recording apparatus 1 according to the present embodiment includes a video input unit 10, a frame rate limiting unit 20, a frame storage unit 30, a frame memory 40, a frame reference unit 50, a video configuration unit 60, a video storage unit 70, and a limited frame rate determination. It is constituted by means 80. The video input means 10 and the moving picture composition means 60 are not limited to one, but may include a plurality of either or both.

  The video recording apparatus 1 is a computer system. That is, the substance of the frame rate limiting means 20, the frame accumulating means 30, the frame memory 40, the frame reference means 50, the moving picture constituting means 60, and the limited frame rate determining means 80 is a program, and each function of each of the computers on which they are executed. It works to have.

  The video input means 10 has a function of inputting an input video A1 as a real-time moving image to the video recording device 1. A video recording device for video data created by an external device such as a video input board or a device having a function for creating video data itself such as a video camera, a television receiver (tuner), a computer screen capture device 1 is included.

  The frame rate limiting means 20 has a function of reducing the frame rate to a given frame rate A10 or lower while maintaining the real time property of the input video A1. This is performed by thinning out frames constituting the input video A1 at a constant rate. That is, when the ratio of the frame rate of the input video A1 to the limited frame rate A10 is k: 1, only one frame is deleted for every k out of the frames constituting the input video A1, and the remaining frames are deleted. The operation of extending the length set in the frame to k times is performed. As a result, a low frame rate video A2 is created.

  The frame memory 40 is a kind of “ring buffer” having the configuration shown in FIG. The “ring buffer” is storage means in which a start record and an end record are adjacent to each other so that sequential writing can be performed endlessly. Actual storage can be realized by using a main memory and a disk (including not only a magnetic disk but also a “semiconductor disk” using a flash memory) constituting the computer.

  In each record of the frame memory 40, “frame information” that is information corresponding to each frame is stored. The frame information includes a “pixel array” and an “attribute” of the frame. The frame attributes include “channel” which is an identifier of the video input means 10 and “start time” and “end time” of the frame.

  The frame accumulating means 30 has a function of taking out all the frames constituting it from the low frame rate video A2 and writing the pixel arrangement and attributes into the frame memory 40 for accumulation. The attribute channel can be obtained by acquiring the identifier of the video input means 10 that has input the input video A1 that is the source of the low frame rate video A2. The start time and end time of the attribute can be obtained by accumulating the lengths of the frames constituting the low frame rate video A2.

  The frame storage unit 30 includes a write position determination unit 31. This has a function of managing a write position A8, which is a record number for writing frame information to the frame memory 40. The position determination unit 31 increments the record number by 1 every time the frame storage unit 30 writes the frame information, and returns it to 1 when the record number exceeds the record number m of the frame memory 40. As a result, the latest m pieces of frame information are always stored in the frame memory 40, and older frame information is sequentially erased.

  The frame reference means 50 has a function of receiving a request from the moving picture composition means 60 and selecting and reading out all frame information stored in the frame memory 40 that meets the frame selection condition A5. . If no frame information suitable for the frame selection condition A5 is found, special “substitute frame information” is created and passed to the moving picture composition means 60. In the substitute frame information not including a valid frame, for example, the color of all the pixels constituting the pixel array is black. Alternatively, a character string or graphic indicating that the frame is invalid is displayed in the pixel array.

The frame reference unit 50 includes a reading position determination unit 51. This has a function of checking the attributes of all the frame information stored in the frame memory 40 with the frame selection condition A5, specifying the most suitable frame information, and notifying the frame reference means 50 of the read position A9. . The frame selection condition A5 is defined as an evaluation function that returns a real value with the attributes included in the frame information, that is, the channel, start time, and end time as independent variables. An example of an evaluation function that defines the frame selection condition A5 is shown in Equation 1 below. The frame reference means 50 passes each piece of frame information to the evaluation function, calculates a value, and specifies the frame information that maximizes the value. For example, the evaluation function A (C, T _S , T _E ) described in Equation 1 returns the maximum value for the newest frame information whose channel is C ₀ and whose end time is before time T ₀ . Therefore, if this evaluation function A is used as the frame selection condition A5, frame information satisfying such conditions can be referred to.

また、動画構成手段６０は、フレーム参照手段５０にフレーム選択条件Ａ５を発行して読み出した選択フレームＡ６を素材として保存動画Ａ７を作成する機能を持つ。動画構成手段６０は、それぞれに独自の方法でフレームの選択と加工を行い、それらを連結して保存動画Ａ７とした上、動画保存手段７０に永久的に保存する。

The moving image composing unit 60 has a function of creating a stored moving image A7 using the selected frame A6 read by issuing a frame selection condition A5 to the frame reference unit 50. The moving picture composing means 60 selects and processes the frames by a unique method, connects them to make a saved moving picture A7, and stores them in the moving picture saving means 70 permanently.

Video is generally very large in data size and difficult to handle. For this reason, the moving image composing means 60 is required to be devised to reduce the amount of data without losing necessary information. Since there are a variety of methods, various methods can be considered for the moving image composing means 60. 4 to 9 show several methods for creating the stored moving image A7 from the low frame rate video A2 as the material.
A. Frame drop (Figure 4)
A method to reduce the data size by lowering the frame rate. Real-time performance is maintained by extending the length of each frame while deleting frames at a fixed rate.
B. Slow motion (Figure 5)
A method to make it easier to see fast movements by reducing the frame rate. The image is slowly displayed by extending the length of each frame without deleting the frame.
C. Digest (Figure 6)
A method of extracting and connecting only moving images at a specific timing, such as trigger signal input. Delete unnecessary frames to reduce the amount of data.
D. Frame processing (Figure 7)
A method of performing various processing on video. Color correction and contour extraction make the video easier to see, reduce image quality to reduce the amount of data, and increase the amount of information displayed by inserting subtitles and graphics.
E. Screen division (Fig. 8)
A method of arranging and displaying multiple videos in one video. Divide the screen into tiles or insert small sub-pictures into the main video so that multiple videos can be observed simultaneously.
F. Channel switching (Fig. 9)
A method of displaying multiple videos while switching over time. While maintaining the quality and real-time characteristics of individual images, multiple images can be observed at once.

  Which method to use depends on the purpose of the recording. For example, conventional camera systems use the method (dropping frames) for street corner security cameras, the method (division of screens) and screens (channel switching) for building surveillance cameras, high-speed cameras and drive recorders. Then, the ro method (slow motion) and the ha method (digest) are often used. In addition to using the above methods (i) to (f) alone, some may be used in combination. When the operation method is determined, frame information to be referred to in order to realize it is determined. Therefore, an evaluation function that returns a large value for such a frame is determined and set as a frame selection condition A5, which is used as frame reference means. Pass to 50.

  The video recording apparatus 1 according to the present embodiment includes a plurality of moving image forming means 60 having different operation methods, and can operate them simultaneously.

  The moving image storage unit 70 is a non-volatile large-capacity storage unit that can store the stored moving image A7 created by the moving image configuration unit 60 over a long period of time. For storage, a magnetic disk or a “semiconductor disk” using flash memory is used.

  Further, the limited frame rate determining unit 80 limits the frame rate A10 to be passed to the frame rate limiting unit 20 based on the write position A8 managed by the write position determining unit 31 and the read position A9 specified by the read position determining unit 51. Has the function to calculate. The limit frame rate A10 is calculated by substituting the write position A8 and the read position A9 into a predefined calculation formula.

  Hereinafter, the specific configuration of the present embodiment will be described in more detail.

  The frame rate limiting means 20 and the limited frame rate determining means 80 are constituent features specific to the video recording apparatus 1 according to the present embodiment. In the following, their actions and effects will be described in detail.

  First, the operation of the frame memory 40 shown in FIG. 3 will be described. This frame memory 40 has m records. Since writing of frame information is performed sequentially, the writing position A8 rotates clockwise by one record each time writing is performed. Therefore, when the reading position A9 is adjacent to a position that is counterclockwise when viewed from the writing position A8 (for example, when the writing position A8 is 1 and the reading position A9 is m as shown in FIG. 10), reading is performed. Is performed on the frame information just written. On the other hand, when the read position A9 is adjacent to the clockwise position when viewed from the write position A8 (for example, when the write position A8 is m and the read position A9 is 1 as shown in FIG. 11). Reading is performed on frame information to be erased soon.

  Here, the concept of “frame memory usage rate” is introduced. This is obtained by dividing “the time from when the frame information is written into the frame memory 40 until it is read out” by “the time from when the frame information is written into the frame memory 40 until it is erased”. It can be calculated by the calculation formula shown in 2.

フレームメモリ使用率は、図１０のような場合にはほぼ０％、図１１のような場合にはほぼ１００％になる。すなわちフレームメモリ使用率が１００％に近いということは、消去される寸前のフレーム情報が読み出されていることを意味する。

The frame memory usage rate is almost 0% in the case of FIG. 10 and almost 100% in the case of FIG. That is, the fact that the frame memory usage rate is close to 100% means that the frame information immediately before being erased has been read.

  When the frame information is erased, the information contained in the frame is lost. Therefore, the video recording apparatus 1 wants to keep the frame memory usage rate below 100%. However, when the frame rate of the video input means 10 is high, when there are a plurality of video input means 10, or when the operation of the moving picture composition means 60 is slow, the rotational speed of the writing position A8 in FIG. Since it exceeds the speed, the frame memory usage rate tends to increase. Therefore, the frame information that the moving image composing means 60 tried to read has already disappeared, and it is likely that the normal stored moving image A7 cannot be created.

  In order to suppress such a situation, the video recording apparatus 1 is provided with a frame rate limiting means 20 and adopts a method of reducing the frame rate of the input video A1 as necessary. The limited frame rate determining means 80 calculates a limited frame rate A10 so as to meet this purpose. That is, the limited frame rate determining means 80 constantly monitors the write position A8 and the read position A9 to calculate the frame memory usage rate, and when this approaches 100%, the limited frame rate A10 is reduced. As a result, the frame memory usage rate starts to decrease, so that it is possible to avoid a situation in which the frame information to be read by the moving picture forming means 60 is erased. When the frame memory usage rate approaches 0%, the limited frame rate A10 may be returned to the initial value again.

  Several methods are conceivable for calculating the limited frame rate A10 from the frame memory usage rate. The frame memory usage rate and the limited frame rate may not be uniquely associated but may have hysteresis. Examples of temporal changes in the frame memory usage rate calculated by simulation are shown in FIGS. The change in the frame memory usage rate varies depending on the calculation method of the limited frame rate A10, and a method of calculating the limited frame rate A10 so as to be directly proportional to the frame usage rate as in the examples of FIGS. Compared to the method of calculating the frame usage rate so that the limited frame rate A10 changes abruptly with a threshold as in the example of FIG. It can be seen that the rate A10 changes stably.

  Hereinafter, a comparison with a method of completely blocking the input video A1 will be described.

  As a method for preventing the loss of the frame information stored in the frame memory 40, there is a conventional technique for completely blocking the input video A1. On the other hand, the video recording apparatus 1 according to the present embodiment does not completely block the input video A1 by setting the limited frame rate A10. Below, the advantage which this method brings is demonstrated.

  In a video recording apparatus that stores and records video as a moving image, a huge data size unique to the moving image often becomes a problem. In a moving image that is a collection of a large number of images, it is not uncommon for the size to exceed 1 gigabyte, and sometimes it reaches 1 terabyte. Too big videos are extremely difficult to handle, move, and browse. For this reason, the video recording device is required to be devised to prevent the moving image from becoming too large. Security cameras and surveillance cameras reduce data size by lowering the frame rate and resolution. In high-speed cameras and drive recorders, the data size is prevented from increasing by limiting the recording time to a short time.

  The video recording apparatus 1 according to the present embodiment can simultaneously operate a plurality of moving image forming means 60 having different operation methods. This makes it difficult to use a method that completely blocks the input video A1 and prevents the loss of frame information. For example, let us consider a case where an instantaneous moving image forming means 60a that operates like a high-speed camera or a drive recorder and a continuous moving image forming means 60b that operates like a security camera or a surveillance camera are operating simultaneously. If the frame rate of the video input means 10 is large, the operation of the instantaneous motion picture composition means 60a cannot catch up and the frame memory usage rate increases. However, if the input video A1 is completely cut off when the frame memory usage rate approaches 100%, the frame information required by the continuous video composition means 60b cannot be obtained, and it is impossible to create a normal stored video A7. become. The video recording apparatus 1 according to the present embodiment does not completely block the input video A1, but only limits the frame rate in order to avoid such a situation. Many continuous moving image forming means 60b do not require an input video A1 with a high frame rate, and therefore are hardly affected even if the frame rate limiting means 20 operates.

  The frame rate limiting unit 20 and the limited frame rate determining unit 80 function as a unit that prevents the loss of frame information in the video recording apparatus 1 and prevents a situation in which a normal stored moving image A7 cannot be created. However, this method is also not universal, and depending on the combination of the moving image forming means 60, as a result of limiting the frame rate of the input video A1, it may appear as a side effect that the video quality of the stored moving image A7 deteriorates. This is likely to be a problem when a plurality of instantaneous moving image forming means 60a are operating simultaneously or when continuous moving image forming means 60b is operating at a relatively large frame rate.

  Next, the user interface will be described.

  FIG. 21 shows a screen example of the video recording apparatus 1 according to the present embodiment. This screen includes an “input video” field, a “recording” field, a “setting” field, and a “status” field.

  In the “input video” column, the input video A1 is displayed in real time. When the video recording apparatus 1 includes two video input means 10, two input videos A1 are displayed as in this example.

  In the “Record” column, an input column for setting the operation of the moving image composing means 60 is displayed. When the video recording apparatus 1 includes two moving image forming means 60, two input fields are displayed. In this example, the first moving image forming means 60 is set to an instantaneous operation, and the second moving image forming means 60 is set to a continuous operation.

  In the “Setting” column, two setting items are displayed. When the “dynamically limit input frame rate” item is checked, the operations of the frame rate limiting unit 20 and the limited frame rate determining unit 80 are enabled. If you don't like the above side effects, uncheck this item. In another item “place frame memory on disk”, it is possible to select whether the frame memory 40 is placed in the main memory or the disk. If the frame memory 40 is placed on a disk having a larger capacity than the main memory but at a low speed, the performance of the video input means 10 having a high frame rate cannot be extracted, but the time that can be recorded retroactively becomes longer.

  In the “status” column, the current frame memory usage rate and the limited frame rate A10 are displayed in real time. The user of the video recording apparatus 1 can look at these numbers and estimate the risk of occurrence of the above-mentioned side effects or review the settings of the moving picture composition means 60 so that the side effects are unlikely to occur.

  As described above, according to the video recording apparatus 1 of the present embodiment, since the writing position determining means for determining the position for writing the frame to the frame memory and the reading position determining means for determining the position for reading the frame from the frame memory are provided. The current writing position and reading position in the frame memory can be specified, and thereby the current usage status of the frame memory can be known. By grasping the usage status of the frame memory in this way, it is possible to provide a video recording apparatus that can prevent video loss due to the frame memory being full and can reliably record video.

  Further, in the present embodiment, the frame rate limiting means for thinning out the frames constituting the video input by the video input means to reduce it to a predetermined limited frame rate, the writing position determined by the writing position determining means, and the reading Since there is a limited frame rate determining means for calculating a limited frame rate based on a reading position determined by the position determining means, a video recording apparatus capable of preventing the frame memory from being filled and recording a video reliably. Can be provided.

  In the present embodiment, the limited frame rate determining unit calculates a limited frame rate that is lower than the frame rate of the video input unit and exceeds 0. It is possible to provide a video recording apparatus capable of continuously recording video without stopping video recording.

  In this embodiment, since the limited frame rate or a value having a correlation with the limited frame rate is displayed, there is a possibility that side effects such as video quality degradation caused by frame rate decimation may occur. The video recording plan can be urged to be reviewed if necessary.

  In addition, since the present embodiment includes means for arbitrarily starting and / or ending the operation of the frame rate limiting means, when occurrence of side effects such as video quality degradation due to frame rate decimation is not allowed, The operation of this function can be stopped.

  In the present embodiment, the video recording apparatus includes one or a plurality of video input means, a frame memory provided in accordance with the number of video input means, and a plurality of video composition means. Since the configuration means operates simultaneously while creating moving images having different frame rates, a plurality of video recording plans having different recording time and video quality balances can be set. If a plurality of video recording plans are combined in accordance with the recording target, video recording that is not overlooked in terms of both recording time and video quality can be realized.

  Each embodiment described above is described in order to facilitate understanding of the present invention, and is not described in order to limit the present invention.

  For example, in the above-described embodiment, a ring buffer including a fixed-length record is used as the frame memory. However, the present invention is not limited to this, and a memory having another structure may be used. However, it is desirable to use a ring buffer as the frame memory in terms of both ease of mounting and performance.

  Moreover, about the operation | movement method of the moving image structure means 60, you may provide not only the method illustrated to said i-F but another method.

  In the screen example shown in FIG. 21, instead of displaying the limited frame rate A10, a frame rate reduction rate that is a ratio of the limited frame rate A10 to the frame rate of the input video A1 may be displayed.

1 video recording device 10 video input means 20 frame rate limiting means 30 frame storage means 31 writing position determining means 40 frame memory 50 frame reference means 51 reading position determining means 60 moving picture composing means 70 moving picture storing means 80 limiting frame rate determining means A1 input Video A2 Low frame rate video A3 Write frame A4 Read frame A5 Frame selection condition A6 Selected frame A7 Saved video A8 Write position A9 Read position A10 Limited frame rate

Claims (6)

At least one video input means;
Frame memory,
A video recording device comprising a plurality of moving image forming means,
The video recording apparatus, wherein the plurality of moving image forming means operate simultaneously while generating moving images having different frame rates. Frame storage means for decomposing the video input by the video input means into frames and writing it into the frame memory;
In accordance with a condition from the moving image forming means, comprising a frame reference means for reading out a corresponding frame from the frame memory,
The frame storage means includes a writing position determining means for determining a position for writing the frame to the frame memory,
The video recording apparatus according to claim 1, wherein the frame reference unit includes a reading position determining unit that determines a position at which the frame is read from the frame memory. Frame rate limiting means for thinning out the frames constituting the video input by the video input means and reducing them to a predetermined limited frame rate;
3. The apparatus according to claim 2, further comprising: a write position determined by the write position determination unit; and a limited frame rate determination unit that calculates the limited frame rate based on a read position determined by the read position determination unit. Video recording device.   4. The video recording apparatus according to claim 3, wherein the limited frame rate determining unit calculates a limited frame rate that is lower than a frame rate of the video input unit and exceeds zero.   5. The video recording apparatus according to claim 3, wherein the limited frame rate or a value having a correlation with the limited frame rate is displayed.   6. The video recording apparatus according to claim 3, further comprising means for arbitrarily starting and / or ending operation of the frame rate limiting means.

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